Affinity Water said the region had received half the normal rainfall since July last year.
Photograph: Gareth Fuller/PA

Households in southern England are being urged to save water after the driest winter period in 20 years.

The driest October to March since 1995-96 has been followed by less than half the average rainfall for April, creating challenging conditions for farmers. The south-east has been worst affected and one water company has advised its customers to take action now to prevent restrictions being imposed later this year.

The impact in the past has tended to be greater for farmers than for residents, for whom the main effect is hosepipe bans.

The National Farmers’ Union (NFU) said: “There remains a risk that groundwater in the south and east may not have recovered sufficiently to avoid the imposition of some drought management actions in late summer … rain-fed crops such as cereals are beginning to suffer from low soil moisture.”

It said irrigation had started early in some areas but added that farmers were remaining calm. A spokesman for Affinity Water, which supplies an average 900m litres of water daily to customers in parts of southern England, said: “Since July 2016, our region has received just over half of the normal rainfall that we would usually expect.

“Due to the low rainfall, many rivers across the south-east of England have seen flows decrease. Our groundwater sources have also been affected by the low rainfall, which is where 60% of the water we supply to our customers comes from.

“We are encouraging our customers to save water to help preserve supplies and minimise the possibility of restrictions this summer.”

Southern Water reiterated its water-saving tips – including taking a shower instead of a bath and making sure the washing machine and dishwasher are full before using them – but stopped short of a warning.

In a statement, it said: “Despite the dry winter, we don’t believe we will need to take measures, such as introducing temporary use bans, previously known as hosepipe bans, in our water supply areas this spring and summer.

“We’re continuing to monitor the situation closely, with clear plans in place to make sure we’re fully prepared, should the relatively dry weather continue in the months ahead.”

The Met Office is expecting some rainfall in the middle of this month before a return to dry conditions.

Its spokesman Grahame Madge said: “I can say that in the next few days it does not look like there is going to be anything particularly meaningful in terms of rainfall.

“After some rainfall in the middle of May, it looks likely drier than average conditions will return towards the end of May.”

The Environment Agency said there were no current water supply issues but it was monitoring the situation.

A spokeswoman said: “We always advise that everyone use water wisely – especially during a period of dry weather – and to follow the advice of their water company should water saving measures be required.

“The Environment Agency, water companies, businesses and farmers are working together to minimise any potential impacts to people and the environment should the dry weather continue.”